1. Field of the Invention
The present invention relates to a method and apparatus for improving adhesion in a railway vehicle by increasing the adhesion coefficient between the rail and a wheel of the railway vehicle.
FIG. 1 shows an improved adhesion device for a railway vehicle which is described in Japanese Laid-open Patent Application No. (OPI) 60-163703. The figures shows a railway wheel 1, a rail 2, and a bogie or carriage 3. A container 4 supported on the bogie 3 contains minute adhesion particles 8. A pipe 5 is provided on the container 4 so as to supply the adhesion particles 8 to a contact surface defined between the wheel 1 and the rail 2. The adhesion particles 8 may be sand or quartz. The pipe 5 has an opening positioned in front of the wheel 1 in the normal running direction of the vehicle and in confrontation with the contact surface between the wheel 1 and the rail 2.
Further, a second pipe 6 is juxtaposed with the first pipe 5 for applying weak pneumatic pressure upon actuation of an electro-magnetic valve 7 so as to direct the minute particles 8 toward the contact surface.
Incidentally, the minute adhesion particles 8 have a particle diameter of 10 to 100 micrometers.
In the conventional adhesion intensifying method applied to railway rolling stock, jets of fine particles of 10-100 micrometers in particle diameter are sent out to the contacting faces of wheels and rails with the aid of weak air pressure. Such a conventional method has a shortcoming in that the particle may be unable to properly reach an intended spot because the trajectory in which the particles flow is curved when vehicles in operation are subjected to a side wind or when turbulent air is generated as the vehicles move.
Another drawback is that the pipe may become clogged with frozen moisture stuck to the interior of the pipe or mingled with the fine particles. The frozen moisture results in impeding the injection of the fine particles.
Since the conventional adhesion intensifier for railway rolling stock is thus constructed, a fixed quantity of sand is jetted out, irrespective of the speed of rotation of the wheel, and more sand than is required is consumed when the vehicle speed is low. On the other hand, insufficient sand is delivered when the vehicle speed is high resulting in a reduction in the coefficient of adhesion. Another problem is that, since a fixed quantity of sand is jetted out, irrespective of the weather conditions, of the conditions of the roadbed or of the load carried by the vehicle, an excess or insufficient quantity of sand may be delivered for those conditions.